2010

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What are the physiological and thermal effects of shortwave diathermy?

1. Thermal

2. Non- thermal

Both occur at the same time

What are the thermal effects of shortwave diathermy?

- Normal heating effects

- increase temps in both the skin and intramuscular layers

- diference between this and conductive heating is the depth of penetration- 3 and 6 * rise at skin level, 2 and 5.5 degrees rise, intra- articular heating ahs also been demonstrated in mm

-soft tissue healing- increase metabolism and cell activity

- draper- showed pulse short wave can increase tissue temp

What are the Non- thermal physiological and therapeutic effects of short wave diathermy?

- relate to effects that occur in tissues that are not associated with a heat change of greater than 1*

- some evidence to support that an alteration of cell ion- binding properties occur, which in turn effects ATP production and protein synthesis. This is presumed to enhance soft tissue healing

What are the absorption depths of shortwave diathermy?

- distance they can travel into the skin

- 1 HDV you have 0.5 penetration depth

- HDV (half depth value) = the distance traveled by the electromagnetic waves into soft tissue as measured from the skin surface, until the electromagnetic energy is reduce by 50%

- PD (penetration depth) = distance within the tissue where 63% of the original energy is absorbed. 1pd= 27% of energy

What is the evidence for the shortwave diathermy?

1. soft tisue healing- conflicting evidence. This has been shown through the use of animals such as rats, dogs, rabbits and guinea pigs where there were successful and non successful evidence

- Humans- through experiments on humans there has been evidence supporting the rate of skin healing with two experiments for it helping the thickness of skin graft and resolve chronic pressure ulcers, reolution of haematomas, ankle sprains,

- limited evidence supporting the relief of pain (OA) no conclusion if effective or not

What are the modes of application for SWD?

- continuous SWD

- Pulsed SWD

What sort of SWD do you use for thermal effects?

- continuous

When do you use a pulsed application of SWD?

- non termal effects are needed

- acture and subacture responses

What pulse frequency do you use for acute?

- pulse between 1 and 1000Hz

- pulse duration fixed at 400us

What are the methods of application of SWD?

- capacitive

- inductive

What is the capactive method of SWD application?

- this method uses 2 capacitive electrodes positioned on either side of a body segment. These electrodes can be rigod plates or flexible pads

1. Capacitor field: - if there is a boundary between materials with different dialectric constants and conductiveness, the electric field is refracted at the boundary spreading

- electrical field in the tissues tends to berefracted at various interfaces

- fat has long conductivity- refracted off - prevents penetration of great depth

2. Inductothermy

- due to eddy currents flowing through the coil

- electromagnetic induction of electrical curents are perpendicular to the direction of the magnetic

What do you need to consider with heating patterns and the uniformity of the field?

- spacing of eletrodes

- size of electrodes

- positioning of electrodes- relative to the tissue

- closer 2-4cm from pt. If one electrode is closer the field will heat more on that side Electrodes come in different sizes

Inductive cable

What are the dosage parameters that need to be used for SWD?

- qualitatively- the level of themal sensation the pt experiences

-quantitatively- total energy delivered by the device at the electrode level

What is the total energy expressed in?

- Watts

C- continuous SWD, total energy = Peak power (pp)

P (pulse) SWD, total energy = mean power (pm)

Pm= Pp x electrical duty cycle

= Pp x ratio of pulse duration to pulse period

How long does it take for the vascular adjustments to occur?

- 15 to 20 mins

- applications need to be at least 20-30 mins long

NOTE to perception of the pt is the only safe guide to heating. Most of the heat will be detected by the themoreceptors in the skin

What are the thermal indications for SWD?

-promote soft tissue healing

- deacrease pain

- reduce jt stiffness

What are the indications for non- thermal of PSWD?

- control pain and oedema

- wound healing

- nerve healing

What are the dangers and precautions of SWD?

- burns

- cardiac pacemakers or implanted neurostimulators

- synthetic materials can melt

- distance from the shortwave machine

- obese pt- fat heate more than mm

- eve- c ant get rid of heat

- pregnancy

What are the contraindications for SWD?

- implanted pacemakers

- metal in or on the surface of tissues

- impaired thermal sensation

- pts unable to contrl their movts

- uncooperative pts

- over the uterus of a pregnant woman

- haemorrhagic conditions

-ischaemis tissues

- malignant tumours

- active tb

- bacteria

- sites of reent venous thrombosis

- pyrexic pt- fever

-over the eyes or testes

- bone epiphyseal region in children

What are the contraindications for SWD continuous only?

- over acute or subacute inflam conditions

- over moist wound dressings

- over a copper bearing IUD

Conduct a thermal sensitivity test

- 2 test tubes

- hot cold

What is the warning for SWD?

When receiving shortwave treatment, all you should feel is a mild comfortable warmth. If you feel more than this or if the heat concentrates in any particular spot or it starts to feel uncomfortable you must call me immediately otherwise you may be in danger of being burnt.

Please do not move or touch any of the equipment during treatment. If you become uncomfortable please call me.

Do you understand what I have said? Do you have any questions? Are you happy for me to proceed?